Explanation of the Use of Aerogels - Case Study Example

Aerogel Name Institution Subject Instructor Date Abstract Aerogels are different classes of non-porous materials which are extremely less dense materials, combining a wide range of extreme and disparate material to form a single material envelope. For instance, the Silica Aerogels are seen to combine low density as minimum as 1 kg/m 3 with extremely low thermal conductivity in the ranges of 15Mw/m/K, significantly high specific surface areas within the ranges of 500-1500M2/g, high optical transparency and a significant low dielectric constant where it is about 1.02 thus, they are high performing insulators, detectors of particles and being used as, supports for catalysts and chemical sensors. Other Aerogels like those made of metals, carbon and carbon nanotubes usually exhibit characteristic like high electrical conductivity thus, being used as electrode substrates in batteries, super capacitor architecture and salination applications. This paper elucidates the aerogel as an engineering material and its application. Table Contents Table Contents 3 1 Introduction 4 1.1 A brief History of Aerogels 5 1.1.1Properties of Aerogels 5 2 Examples of the material 6 3 Case study of an Aerogel Building 6 3.1 The Solar Decathlon house (Deb, 2012) 7 4 Explanation of the use of the relevant material 8 5 Information on appropriate and inappropriate engineering use of Aerogel 10 5.1Limitations on use of Aerogels 10 6 Environmental Effects 11 7 Conclusions 11 1 Introduction Initially, Aerogel products were thought to be extremely brittle thus, finds no utilization in industries. This is attributed to their brittleness and extremely low compressive strength. In the previous years, the emergence of Aerogels has overcome the limitations. For instance, the microfiber blankets and fine particles which are low cost and, their development have caused a significant impact in the energy efficiency particularly in the oil and gas industries, performance coating industries and day lighting (Ashby Ferreira and Schodek, 2009). There are also monolithic Aerogels which leverage all the better properties offered by the Aerogels more than the other forms thus, bringing an untapped potential for more novel applications. In the market today, the Aerogel technologies have formed a new class of mechanically super performing monolithic aerogel known as the AirloysTM. It has superior strength and durability as needed for engineering materials (Mortensen, 2007). These mechanical properties of the Airloys overcome all the limitations exhibited by the Aerogels through the incorporated polymer nanostructures. As stated above, these are solids with the lowest known densities with the ability to stand 200 greater loads than their weight. They exhibit low thermal conductivities, thus they are being applied as insulators in buildings as noted by Aegerter (2011). Their melting point has been found to be at the level of 1200 degree centigrade. They also have the capacities to damp vibrations and sound. In the future, this material may be applied in construction work as well as the insulation material particularly cladding. This causes a significantly low thermal coefficient of heat transfer the aerogels consist of microscopic nano-meter particles with diameters of about 1-10 nanometer sticking together to form long chain with a myriad of contact points to form a stable 3 dimensional network. 1.1 A brief History of Aerogels The first Aerogel were developed in 1931 by Steven.S.Kistler, these were forgotten up to 1970 when the French government begun the initiative of seeking for a method to use porous materials for the storage of oxygen and other rocket fuels (Mortensen, 2007). The quest led to a major interest in this field like the use of sol-gel chemistry in the preparation of silica Aerogel preparation. In this, reacting a metal alkoxide and water produces a metal hydroxide and condensation succeeds between the two hydroxides. After this, the molecular weight of the compound starts to increase as the molecules continue to gro. Thereafter, linking occurs to make an alcove (Aramendía and Bevy, 2005). Then the drying of the alcove under super critical alcohol conditions leads to the formation of Aerogel. 1.1.1Properties of Aerogels The microstructure: these compounds consist of particles with diameters of approximately 1-10 nanometers. This extremely small diameter causes them to have an exceptionally high surface to volume ratio (Mortensen, 2007). This interior chemistry of the Aerogels affects the chemical and physical properties of the Aerogels thus making it to be used as adsorbents and catalyst substrate. 1.1.1.1Thermal property It is astonishing to realize that one inch insulation by silica Aerogel is equivalent to that provided by twenty glass window panes. The heat loss through windows accounts is equivalent to 30% of the total heat loss (Aegerter, 2011). This means that an efficiently and perfectly designed window pane will significantly reduce the heating and cooling costs in buildings.at the temperatures above 200 degrees centigrade, the dorminat method of heat transfer is by radiation and with the use of silica aero gels, this greatly reduced. This attribute can be achieved if carbon is added to the Aerogel either before or after critical drying. This is because carbon is an effective infra red radiation absorber and it also leads to significant increase in the mechanical strength of Aerogels. 1.1.1.2Transparency Aerogels have significantly small pores which cannot scatter light but, at some times the pores might be large leading to scattering of light hence the hazy appearance. The Aerogels produced now appear cloudy but studies are being made to ensure that, transparent Aerogels are formed which could lead to formation of high insulation windows and super speed computers. 2 Examples of the material The different products of Aerogels are monolithic, the clamshell preformed insulation, the powders and the flexible blankets. 3 Case study of an Aerogel Building Aerogel has been proved to be an excellent material in thermal insulation and can be either translucent or clear. Its use is in the design of transparent shells in the buildings. The use of transparent silicon Aerogel will be a great milestone in the construction industry. A Swedish company the Air glass is making great advancements in the development of recent materials for windows glazing which is designed from a vacuum sealed Aerogel layer which is sandwiched between two glass layers (Mortensen, 2007). The production in this plant is still at its early stages with a production rate of about 3-6m square per month. The first test of this as an insulator was done in the Solar Decathlon House in Georgia Institute of Technology where it is applied to give a semi transparent roof. 3.1 The Solar Decathlon house (Deb, 2012) The translucent layers have the capacity to capture daylight when the light condition is poor and disperses it in space (Viardot, 2004). This has made it to be applied as illumination in galleries, museums, sports halls and libraries. Another area where it is applied is in Cryogenic piping. Here it has appeared to offer great advantages since it ensures: It also causes increased speeds in installation and flexibility in the industrial models. Reduced infrastructure costs in terms of pipes, racks and pads. The maintenance costs are significantly reduced since due to its high durability, reliability and thermal stability. There is improved savings through an efficient logistic and inventory management Figure 2 Cryogenic piping (Deb, 2012) 4 Explanation of the use of the relevant material Thermal insulation- One inch Aerogel insulation is equivalent to insulation provided by 20 windowpanes, thus it is used in buildings for insulation purposes. Microelectronics-Aerogels have a dielectric constant as low as 2 nearly equivalent to that of air. This has been used by researchers to increase the speed of computing in computers for the future. The improvement in the micro electric field is attributed to the improved crystal growth process. Silica crucible is of immense advantage since its transparency enables the detection crystallization from the front. It has also been noted that silica Aerogel do not suffer wetting by metals like lead, zinc, Germenium, Germenium silicate and Scadinadium (Sn) and also there is no chemical reaction with the melts formed. In future, its application will help in the study of solid/liquid interface in real time, the crystallization temperature gradient and the growth velocity in silica Aerogel moulds. Space technology- Aerogel has found its application in catching stardust in space. It has been found that the particles from comets are significantly smaller as compared to sand, but they hit the Aerogel at extremely high speeds of about 6 km/sec (Ashby Ferreira and Schodek, 2009). This impact is so huge such that, if another material apart from Aerogel is used, the particle would vaporize or become distorted. Engineers used Aerogel insulators in the Mars mission to replace a 23-pound Sojourner with 6 pounds thus saving the eight by approximately 20% thus reducing the cost significantly. Kinetic energy absorption- at first aerogels appears as bad choices for cushioning. Silica Aerogel has a very low density and solid network collapsing spreads the impact over an extended time. Aerogels help reduce the rebound effects which could have damaged e product. This is applied for personal protection in vehicles and covering of protective equipment. It is also used in: Cosmetics Drug delivery systems and in pharmacy It’s also used for making space suits, the insulation of Cryogenic tank and making of ant sloshing in tanks. Sportswear and sports apparels like security shoes, sports shoes, and tennis rackets In architecture where it is applied for illumination purposes, isolation of walls and construction of superlight concrete. In foundry work where it is used in acrogenic binders, foundry sands and Aerogel granules. It is also used for design of SHG ( non linear optics) The formation of transparent metals 5 Information on appropriate and inappropriate engineering use of Aerogel From the excellent thermal insulating properties of aerogel , it follows that the critical surface temperature is not reached and water vapour condensation is not experienced at the condition borderlines hence the windows do not have mist or fog. The Aerogel filled windows do not lose thermal resistance over a period of time as compared to the gas/vaccum filled ones (Aramendía and Bevy, 2005). They exhibit gradual reduction in thermal resistances in a period of time attributed to the thermal leakage by the inert gases. In future, the application of Aerogels is foreseen to rise since double glazing using inert gases has reached its limit and the aerogels will bring better properties in the industry. With the decreasing cost of Aerogels, it is indicative that this will be used as instant in future. This material has better insulating properties yet its weight is significantly low; about a thousandth of its mass thus we shall have extra light shells with reduced static loads. 5.1Limitations on use of Aerogels Aerogels have limited use in industrial processes since once they come into contact with water; they tend to turn back into gel. Consequently, the present Aerogels appear in blue tinge thus not clear and cannot be used in transparent plastics. Similarly, it has proved not easy to mass produce aerogels for engineering use since aerogel with precise properties has never been produced in space under gravity (Ashby Ferreira and Schodek, 2009). The difficulty in this is attributed to the complexity in maintaining the pore sizes and the dimensions and proportions of the parts. Recent research has shown that these difficulties can be overcame if production is done in weightless conditions .the study is not purposed to produce unique materials in states of weightlessness since with the state of astronautics cannot produce them cost effectively. The first zero gravity production experiments was done in 1996 using star fire rockets. In this experiment, it was realized that the material had four to five better parameters as compared to when produced on earth. However, they have found use in construction works where the blue color is not an inhabitant thus they can be used in swimming pools. 6 Environmental Effects It is evident that the Aerogels are from silica whose disposal is mainly natural. After disposal, they crush into a fine powder identical to the common substances on earth like sand thus, the silica Aerogels environmentally safe, non toxic and not flammable as noted by Mortensen (2007). 7 Conclusions As it has been seen, Aerogels have a myriad of applications but its increased use depends on its availability which is a function of the technology of manufacturing developed. It is envisaged that Aerogels will soon be as plenty as plastics today. In the markets, the prices of Aerogel products are affordable. It is eminent that the insulation capacity of Aerogels will significantly reduce energy consumption thus helping reducing pollution through reduced greenhouse gas emissions. Aerogels are environmentally benign and sustainable meaning they are the best for future construction work. We can therefore conclude that these are the best Civil Engineering materials for the 21st Century. References Aegerter, M. A., 2011. Aerogels Handbook. New York, NY, Springer. Aramendía, M. A., and Bevy, L. P., 2005. New developments in catalysis research. New York, Nova Science Publ. Ashby, M. F., Ferreira, P. J. S. G., and Schodek, D. L., 2009. Nanomaterials, nanotechnologies and design an introduction for engineers and architects. Amsterdam, Butterworth-Heinemann. Deb, S., 2012. Aerogel: Revolutionary advancement in thermal technology. B. Tech, Mortensen, A., 2007. Concise encyclopedia of composite materials. Amsterdam, Elsevier. Viardot, E., 2004. Successful marketing strategy for high-tech firms. Boston, Mass. [u.a.], Artech House. Read More